Heat-storage composition

ABSTRACT

A heat-storage composition includes a resin and a heat storage material. The composition has a viscosity of 100 to 1,000 dPa·s, as measured with a cylinder-type rotational viscometer. The composition also has a storage elastic modulus (G′) of 3 Pa or more at an angular frequency of 1 rad/s, as measured by a dynamic viscoelasticity measurement method at a temperature of 25° C. and at a strain of 0.1%.

TECHNICAL FIELD

One or more embodiments of the present invention relate to aheat-storage composition which forms a heat storage material havingflexibility advantageously used for maintaining an appropriatetemperature for housing spaces of houses and the like and interiorspaces of automobiles and the like.

BACKGROUND

Recently, strong demands are being made on housing spaces of houses,offices, and the like wherein energy should be saved, and, in thebuilding materials used in houses and the like, materials thatcontribute to energy savings are demanded. Generally, heat insulatingmaterials are used in floors, ceilings, walls and the like in an attemptto improve the air-conditioning or heating efficiency, and, for furthersaving energy, studies are made on various types of materials.Similarly, with respect to closed spaces of automobiles, aircraft andthe like, and the inside of refrigerators of refrigerator trucks and thelike, demands for saving energy are increasing.

With respect to the above-mentioned material, for example, a materialhaving an encapsulated phase change material mixed into plasterboard isdisclosed (see PTL 1). Further, as a material using a flexible material,a heat-storage thermoplastic resin sheet containing a heat storagematerial in a thermoplastic resin (see PTL 2) and the like aredisclosed.

PTL 1: JP-A-2003-284939

PTL 2: JP-A-2009-51016

The above-mentioned material having a phase change material mixed intoplasterboard is used in walls or the like so as to increase the heatcapacity of the walls or the like, achieving energy savings. However,this material is poor in flexibility or handling properties, and hencethe mode of the use of the material is limited.

On the other hand, the above-mentioned sheet using a thermoplastic resinhas flexibility due to the use of the thermoplastic resin, but has athickness as small as about 100 μm. For realizing heat storageperformance useful for housing spaces and the like, the heat storagesheet is required to have an increased thickness, but thick filmapplication is difficult using the resin composition used for the abovesheet.

SUMMARY

One or more embodiments of the present invention provide a heat-storagecomposition which is advantageous not only in that the compositionenables thick film application, but also in that, when the compositionis subjected to thick film application, slump is unlikely to occur.

Further, one or more embodiments of the present invention provide aheat-storage composition which is advantageous in that the compositionis easily kneaded during the preparation of the composition.

One or more embodiments of the present invention are directed to aheat-storage composition including a resin and a heat storage material,having a viscosity of 100 to 1,000 dPa·s as measured with acylinder-type rotational viscometer, and having a storage elasticmodulus (G′) of 3 Pa or more at an angular frequency of 1 rad/s asmeasured by a dynamic viscoelasticity measurement method at atemperature of 25° C. and at a strain of 0.1%.

The heat-storage composition of one or more embodiments of the presentinvention has a specific viscosity and viscoelasticity, and thereforeenables thick film application, and, when the composition is subjectedto thick film application, slump is unlikely to occur, and hence a thicksheet having a thickness as large as more than 1 mm can beadvantageously formed from the heat-storage composition. Thus, a thicksheet can be easily and continuously formed by application from theheat-storage composition, and hence a thick film can be formed from theheat-storage composition without using a method of filling a formedframe with a coating liquid or a method of stacking a plurality oflayers on one another, and therefore a heat storage sheet havingadvantageous heat storage performance can be produced at a low cost.Further, even though the heat-storage composition does not have a veryhigh viscosity, the composition advantageously enables thick filmapplication, and hence blending or kneading of the composition beingprepared is not difficult, enabling advantageous preparation of thecomposition.

The heat-storage composition of one or more embodiments of the presentinvention is advantageous in that a flexible heat storage sheet havingan increased thickness can be formed from the composition with ease andat a low cost. The heat storage sheet formed from the composition can beadvantageously applied to various uses that are required to achieveenergy savings, such as materials applied to wall materials and wallpaper for housing spaces of houses and the like, interior spaces ofautomobiles, electric trains, aircraft, agricultural hothouses and thelike, closed spaces, e.g., the inside of refrigerators of refrigeratortrucks and refrigeration equipment, and the inside of aircraft, andelectric parts which generate heat, e.g., a CPU and a storage batteryfor personal computer.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The heat-storage composition of one or more embodiments of the presentinvention includes a resin and a heat storage material, has a viscosityof 100 to 1,000 dPa·s as measured with a cylinder-type rotationalviscometer, and has a storage elastic modulus (G′) of 3 Pa or more at anangular frequency of 1 rad/s as measured by a dynamic viscoelasticitymeasurement method at a temperature of 25° C. and at a strain of 0.1%.

[Resin]

The resin used in the heat-storage composition of one or moreembodiments of the present invention is a resin component which forms amatrix upon forming a sheet. As the resin, various types of resins, suchas thermoplastic resins, thermosetting resins, and ultraviolet curingresins, can be used. Especially, thermoplastic resins can be preferablyused from the viewpoint of facilitating the formation of a coating film.Examples of thermoplastic resins include a vinyl chloride resin, anacrylic resin, a urethane resin, an olefin resin, an ethylene-vinylacetate copolymer, a styrene-butadiene resin, a polystyrene resin, apolybutadiene resin, a polyester resin, a polyamide resin, a polyimideresin, a polycarbonate resin, a 1,2-polybutadiene resin, a polycarbonateresin, and a polyimide resin. Of these, a vinyl chloride resin ispreferably used because formability at low temperatures anddispersibility of the heat storage material are readily obtained.

In one or more embodiments where a vinyl chloride resin is used, it ispreferred that a sol cast film is formed using the heat-storagecomposition using vinyl chloride resin particles because a heat storagesheet can be formed at low temperatures. The heat-storage composition isa composition in a paste state, which has a heat storage materialdispersed or suspended in a resin composition containing vinyl chlorideresin particles and a plasticizer.

The vinyl chloride resin particles of one or more embodiments preferablyhave an average particle diameter of 0.01 to 10 μm, preferably 0.1 to 5μm. In the heat-storage composition, the vinyl chloride resin particlesmay be in a state in which the particles are directly dispersed in thecomposition, or may be in a state in which the particles as primaryparticles suffer aggregation to form spherical secondary particles andthe secondary particles are dispersed in the composition. Alternatively,the vinyl chloride resin particles may be a mixture of particles havingdifferent particle diameters and having two or more peaks of theparticle size distribution. The particle diameter can be measured by alaser method or the like.

The shape of the vinyl chloride resin particles used in the heat-storagecomposition of one or more embodiments is preferably a substantiallyspherical shape because advantageous fluidity is readily obtained and achange of the aged viscosity is small. With respect to the vinylchloride resin particles, those which are produced by emulsionpolymerization or suspension polymerization are preferred because theparticles of a spherical shape can be easily obtained and it is easy tocontrol the particle size distribution of the particles.

In one or more embodiments, the polymerization degree of the vinylchloride resin used is preferably 500 to 4,000, more preferably 600 to2,000. Further, when the polymerization degree is in the above range, itis easy to adjust the viscosity measured by a rotational viscometer andthe steady shear viscosity to those in the respective preferred rangesin one or more embodiments of the present invention.

With respect to the vinyl chloride resin particles used in one or moreembodiments of the present invention, commercially available vinylchloride resin particles can be appropriately used, and, for example,there can be mentioned ZEST PQ83, PWLT, PQ92, P24Z, and the like,manufactured by Shin Dai-ichi Vinyl Corporation, and PSL-675, 685, andthe like, manufactured by Kaneka Corporation.

In one or more embodiments where a thermoplastic resin is used as aresin forming a heat storage sheet, the content of the thermoplasticresin is preferably 10 to 80% by mass, more preferably 20 to 70% bymass, further preferably 30 to 60% by mass. When the content of thethermoplastic resin is in the above range, the resin matrix in the sheetcan be advantageously formed, facilitating the formation of a sheethaving flexibility and toughness. Further, when the content of thethermoplastic resin is in the above range, it is easy to adjust thestorage elastic modulus to a value in the range in one or moreembodiments of the present invention.

[Plasticizer]

When a thermoplastic resin is used as the resin used in the heat storagesheet of one or more embodiments of the present invention, from theviewpoint of easily securing excellent application properties and filmforming properties, it is preferred to use a plasticizer and thethermoplastic resin in combination. With respect to the plasticizer, anepoxy plasticizer, a methacrylate plasticizer, a polyester plasticizer,a polyether ester plasticizer, an aliphatic diester, plasticizer, atrimellitic acid plasticizer, an adipic acid plasticizer, a benzoic acidplasticizer, a phthalic acid plasticizer, or the like can beappropriately used. Two or more types of plasticizers may be usedappropriately in combination. When the heat storage sheet is used in theapplication of building materials for houses and the like and theapplication of automobiles and the like, it is preferred to use anon-phthalic acid plasticizer other than the phthalic acid plasticizerswhich could adversely affect a human body.

With respect to the plasticizer of one or more embodiments, varioustypes of plasticizers which are commercially available can beappropriately used, and examples of epoxy plasticizers include MonocizerW-150, manufactured by DIC Corporation; SANSO CIZER E-PS, E-PO, E-4030,E-6000, E-2000H, E-9000H, manufactured by New Japan Chemical Co., Ltd.;ADK CIZER O-130P, O-180A, D-32, D-55, manufactured by ADEKA Corporation;and KAPDX S-6, manufactured by Kao Corporation, examples of polyesterplasticizers include Polycizer W-2050, W-2310, W-230H, manufactured byDIC Corporation; ADK CIZER PN-7160, PN-160, PN-9302, PN-150, PN-170,PN-230, PN-7230, PN-1010, manufacturedbyADEKACorporation; D620, D621,D623, D643, D645, D620N, manufactured by Mitsubishi ChemicalCorporation; and HA-5, manufactured by Kao Corporation, examples oftrimellitic acid plasticizers include Monocizer W-705, manufactured byDIC Corporation; ADKCIZERC-9N, manufactured by ADEKA Corporation; andTOTM, TOTM-NB, manufactured by Mitsubishi Chemical Corporation, andexamples of benzoic acid plasticizers include Monocizer PB-3A,manufactured by DIC Corporation; and JP120, manufactured by MitsubishiChemical Corporation.

In one or more embodiments of the present invention, among theabove-mentioned plasticizers, a plasticizer capable of being gelled atlow temperatures can be especially preferably used because it is easy toprevent the heat storage material or plasticizer from oozing. Theplasticizer preferably has a gelation end-point temperature of 150° C.or lower, more preferably 140° C. or lower, further preferably 130° C.or lower, further preferably 120° C. or lower, especially preferably110° C. or lower. With respect to the gelation end-point temperature, atemperature at which the light transmission properties of the gelledfilm become constant can be determined as a gelation end-pointtemperature. Examples of the plasticizers having excellentlow-temperature formability include an epoxy plasticizer, a polyesterplasticizer, and a benzoic acid plasticizer. These plasticizers havingexcellent low-temperature formability are preferred because advantageousheat storage properties as well as toughness of the resin matrix can beespecially easily obtained. Further, from the viewpoint of the heatresistance and low-temperature formability, an epoxy plasticizer and apolyester plasticizer can be especially preferably used.

The gelation end-point temperature is specifically determined asfollows. A composition having a vinyl chloride resin for paste (degreeof polymerization: 1,700), the plasticizer, and a heat stabilizer(Ca—Zn) mixed in a mass ratio of 100/80/1.5 is placed between a glassplate and a prepared slide, and the temperature is increased at atemperature increase rate of 5° C./min, and a change of the lighttransmission properties is observed using a hot stage for microscopicexamination (Metter 800), and a temperature at which the lighttransmission properties of the composition become constant is determinedas a gelation end-point temperature.

The plasticizer used in one or more embodiments of the present inventionpreferably has a viscosity at 25° C. of 1,500 mPa·s or less, morepreferably 1,000 mPa·s or less, further preferably 500 mPa·s or less,especially preferably 300 mPa·s or less. When the viscosity of theplasticizer is in the above range, the viscosity of the heat-storagecomposition can be suppressed to be low, making it possible to increasethe filling ratio of the heat storage material. Further, when theviscosity of the plasticizer is in the above range, it is easy to adjustthe viscosity measured by a rotational viscometer and the steady shearviscosity to those in the respective preferred ranges in one or moreembodiments of the present invention. With respect to the conditions forthe plasticizer viscosity measurement, the measurement can be made underthe conditions employed in the below-mentioned Examples.

The plasticizer used in one or more embodiments of the present inventionpreferably has a weight average molecular weight of 200 to 3,000, morepreferably 300 to 1,000. When the weight average molecular weight of theplasticizer is in the above range, the plasticizer per se is unlikely toooze out of the composition and the viscosity of the heat-storagecomposition can be suppressed to be low, making it possible to increasethe filling ratio of the heat storage material. Further, when the weightaverage molecular weight of the plasticizer is in the above range, it iseasy to adjust the viscosity measured by a rotational viscometer and thesteady shear viscosity to those in the preferred ranges in one or moreembodiments of the present invention. The weight average molecularweight (Mw) is a value measured by gel permeation chromatography(hereinafter, abbreviated to “GPC”) using a calibration curve obtainedwith respect to polystyrene. The GPC measurement can be conducted underthe conditions shown below.

<Conditions for Measurement of a Weight Average Molecular Weight>

Measuring apparatus: Guard column “HLC-8330”, manufactured by TosohCorp.Columns: “TSK SuperH-H”, manufactured by Tosoh Corp.

-   -   +“TSK gel SuperHZM-M”, manufactured by Tosoh Corp.    -   +“TSK gel SuperHZM-M”, manufactured by Tosoh Corp.    -   +“TSK gel SuperHZ-2000”, manufactured by Tosoh Corp.    -   +“TSK gel SuperHZ-2000”, manufactured by Tosoh Corp.        Detector: RI (Differential refractometer)        Data processing: “GPC-8020 Model II Version 4.10”, manufactured        by Tosoh Corp.        Column temperature: 40° C.        Developing solvent: Tetrahydrofuran (THF)        Flow rate: 0.35 mL/minute        Sample: A 1.0% by mass tetrahydrofuran solution, in terms of a        resin solids content, which has been subjected to filtration        using a microfilter (100 μl)        Standard sample: In accordance with the measurement manual of        the above-mentioned “GPC-8020 Model II Version 4.10”, the        monomodal polystyrenes having known molecular weights shown        below were used.

<Standard Sample: Monomodal Polystyrenes>

“A-300”, manufactured by Tosoh Corp.

“A-500”, manufactured by Tosoh Corp.

“A-1000”, manufactured by Tosoh Corp.

“A-2500”, manufactured by Tosoh Corp.

“A-5000”, manufactured by Tosoh Corp.

“F-1”, manufactured by Tosoh Corp.

“F-2”, manufactured by Tosoh Corp.

“F-4”, manufactured by Tosoh Corp.

“F-10”, manufactured by Tosoh Corp.

“F-20”, manufactured by Tosoh Corp.

“F-40”, manufactured by Tosoh Corp.

“F-80”, manufactured by Tosoh Corp.

“F-128”, manufactured by Tosoh Corp.

“F-288”, manufactured by Tosoh Corp.

When the heat storage material used in one or more embodiments of thepresent invention is a heat storage material in the form ofmicrocapsules containing the heat storage material in a resin outershell, among the above plasticizers, it is preferred to use aplasticizer such that an HSP distance between the heat storage materialused and the plasticizer is 6 or more. By using the plasticizer,elimination of an eliminating component from the heat storage sheet athigh temperatures can be suppressed, facilitating achievement ofadvantageous heat resistance such that volume shrinkage is unlikely tooccur even at high temperatures. In a formed article comprising a resincomposition containing a general thermoplastic resin and plasticizer andcontaining no heat storage material, large volume shrinkage is unlikelyto occur even at high temperatures. However, in a heat storage sheetcontaining a heat storage material, large volume shrinkage likely occursat high temperatures. In one or more embodiments of the presentinvention, when the HSP distance between the heat storage material andthe plasticizer is in the above range, incorporation of the plasticizer,which causes an eliminating component in a large amount at hightemperatures, into the heat storage material is suppressed, so that theoccurrence of volume shrinkage at high temperatures is more likely to besuppressed, facilitating achievement of advantageous heat resistance.From the viewpoint of easily obtaining advantageous heat resistance, theHSP distance is preferably 7 or more, more preferably 8 or more. Withrespect to the upper limit of the HSP distance, there is no particularlimitation as long as the plasticizer is generally used as aplasticizer, but, from the viewpoint of easily obtaining advantageouscompatibility and formability, the HSP distance is preferably 40 orless, more preferably 30 or less, further preferably 25 or less.

The HSP distance is an index indicating the solubility betweensubstances using a Hansen solubility parameter (HSP). The Hansensolubility parameter indicates solubility using a multi-dimensional(typically three-dimensional) vector, and the vector can be representedusing a dispersion term, a polar term, and a hydrogen bond term. Thedegree of similarity of the vector is indicated by a distance betweenthe Hansen solubility parameters (HSP distance).

With respect to the Hansen solubility parameter, values for referenceare shown in various documents, and, for example, there can be mentionedHansen Solubility Parameters: A User's Handbook (Charles Hansen et. al.,2007, the 2nd edition) and the like. Alternatively, using commerciallyavailable software, for example, using Hansen Solubility Parameter inPractice (HSPiP), a Hansen solubility parameter can be determined basedon the chemical structure of a substance. The determination is made fora solvent temperature of 25° C.

With respect to a preferred combination of the plasticizer and the heatstorage material of one or more embodiments, for example, when the heatstorage material having an acrylic outer shell is used, an epoxyplasticizer, a polyester plasticizer, a trimellitic acid plasticizer, orthe like can be preferably used. When the heat storage material having amelamine outer shell is used, an epoxy plasticizer, a polyesterplasticizer, a trimellitic acid plasticizer, a benzoic acid plasticizer,or the like can be preferably used. Especially an epoxy plasticizer ispreferred because various properties, such as a heat resistance, can beadvantageously obtained.

Further, in one or more embodiments of the present invention, from theviewpoint of advantageously constituting the resin matrix of a formedarticle, the HSP distance between the thermoplastic resin and theplasticizer used is preferably 15 or less, more preferably 12 or less.The lower limit of the HSP distance is not particularly limited, but ispreferably 1 or more, more preferably 2 or more, further preferably 3 ormore.

In one or more embodiments where the heat storage material in the formof microcapsules containing the heat storage material in a resin outershell is used, there can be preferably used a plasticizer such that,when the plasticizer is mixed into the heat storage material used, anabsorption of the plasticizer into 100 parts by mass of the heat storagematerial is 150 parts by mass or less, as measured in accordance withJIS K5101-13-1. By using the plasticizer, elimination of an eliminatingcomponent from the heat storage sheet at high temperatures can besuppressed, enabling achievement of advantageous heat resistance suchthat volume shrinkage is unlikely to occur even at high temperatures.From the viewpoint of readily obtaining advantageous heat resistance,the absorption of the plasticizer is preferably 140 parts by mass orless, more preferably 135 parts by mass or less, further preferably 130parts by mass or less. With respect to the lower limit of the absorptionof the plasticizer, there is no particular limitation as long as theplasticizer is generally used as a plasticizer, but, from the viewpointof easily obtaining advantageous compatibility and formability, theabsorption of the plasticizer is preferably 5% by mass or more, morepreferably 10% by mass or more. Further, when the absorption of theplasticizer is in the above range, it is easy to adjust the storageelastic modulus of the composition to a value in the preferred range inone or more embodiments of the present invention.

The absorption of the plasticizer of one or more embodiments is measuredby the method for measuring an oil absorption in accordance with JISK5101-13-1. Specifically, a sample obtained by weighing 1 to 20 g of aheat storage material according to the expected absorption is placed ona glass plate, and a plasticizer is dropwise added to the sample from aburette so that 4 to 5 droplets of the plasticizer are added at a time.After each addition, the plasticizer is kneaded into the sample using apalette knife made of steel. This is repeated and the dropwise additionof the plasticizer is continued until a solid mass of the plasticizerand sample is formed. Thereafter, one droplet of the plasticizer isadded at a time and completely kneaded into the mass, and this isrepeated, and a point in time when the mass has become a smooth paste isdetermined as an end point, and the absorption at the end point is takenas an absorption of the plasticizer. The paste is such smooth that thepaste can be spread without being cracked or crumbling into small piecesand lightly adheres to a measuring plate.

The content of the plasticizer in the heat storage sheet of one or moreembodiments is preferably 5 to 75% by mass, more preferably 10 to 70% bymass, further preferably 20 to 60% by mass, especially preferably 20 to40% by mass. When the content of the plasticizer is in the above range,excellent application properties and formability can be readilyobtained. With respect to the proportion of the contained plasticizer tothe thermoplastic resin, from the viewpoint of easily adjusting theviscosity of the composition to a value in the range in one or moreembodiments of the present invention, the amount of the plasticizer,relative to 100 parts by mass of the thermoplastic resin, is preferably30 to 150 parts by mass, more preferably 40 to 130 parts by mass,further preferably 50 to 120 parts by mass.

[Heat Storage Material]

With respect to the heat storage material of one or more embodiments,there is no particular limitation as long as it has heat storageproperties, and there can be used a heat storage material of a latentheat type, a heat storage material of a sensible heat type, and a heatstorage material of a chemical reaction type utilizing absorption ofheat or generation of heat caused due to a chemical reaction. Of these,a heat storage material of a latent heat type is preferred because thematerial with a small volume readily secures a large amount of energy,and it is easy to control the heat absorption or radiation temperatureof the material.

With respect to the heat storage material of a latent heat type (phasechange material) of one or more embodiments, taking into considerationthe potential oozing of the material during melting due to a phasechange and the like and the dispersibility of the material upon mixing,preferred are heat storage particles in the form of capsules having aphase change material, such as a paraffin, contained in an outer shellmade of an organic material or the like. In one or more embodiments ofthe present invention, when the heat storage particles having an outershell are used, the HSP distance is calculated based on the HSP of thematerial used in the outer shell of the heat storage particles. In theheat storage sheet of one or more embodiments of the present invention,even when the heat storage material containing a phase change material,such as a paraffin, in an outer shell made of an organic material isused, the outer shell is unlikely to suffer embrittlement due to aplasticizer, so that the heat storage material is unlikely to bedamaged.

With respect to the heat storage particles of one or more embodiments,examples of those using an outer shell made of a melamine resin includeThermo Memory FP-16, FP-25, FP-27, FP-31, FP-39, manufactured byMitsubishi Paper Mills Limited, and RIKEN-RESIN PMCD-15SP, 25SP, 32SP,manufactured by Mikiriken Industrial Co., Ltd. Examples of heat storageparticles using an outer shell made of silica include RIKEN-RESIN LA-15,LA-25, LA-32, manufactured by Mikiriken Industrial Co., Ltd., andexamples of heat storage particles using an outer shell made of apolymethyl methacrylate resin include Micronal DS5001X, 5040X,manufactured by BASF AG.

The particle diameter of the heat storage particles of one or moreembodiments is preferably about 10 to 1,000 μm, more preferably 50 to500 μm. With respect to the particle diameter of the heat storageparticles, it is preferred that the particle diameter of the primaryparticles is in the above range, but it is also preferred that the heatstorage particles having a primary particle diameter of 1 to 50 μm,preferably 2 to 10 μm suffer aggregation to form secondary particles,and the particle diameter of the secondary particles is in the aboverange. By using the above-mentioned heat storage particles, it is easyto adjust the storage elastic modulus to a value in the range in one ormore embodiments of the present invention, and, particularly, thesecondary particle diameter of the heat storage particles is preferably500 μm or less, more preferably 300 μm or less, especially preferably100 μm or less.

Such heat storage particles are easily damaged due to a pressure or ashear, but, by virtue of having the construction in one or moreembodiments of the present invention, a damage of the heat storageparticles can be advantageously suppressed, so that oozing or leakage ofthe heat storage material from the particles is unlikely to occur.Especially when the outer shell is formed from an organic material,there is a fear that the particles are damaged due to temperatures.However, the heat storage sheet of one or more embodiments of thepresent invention is advantageous in that even when using the phasechange material having such an outer shell, oozing or leakage of theheat storage material can be advantageously suppressed. All the heatstorage particles used in the heat storage sheet do not necessarily havea particle diameter in the above-mentioned range, and preferably 80% bymass or more of, more preferably 90% by mass or more of, especiallypreferably 95% by mass or more of the heat storage particles in the heatstorage sheet are the heat storage particles having a particle diameterin the above-mentioned range.

In one or more embodiments, the phase change material undergoes a phasechange at the melting point thereof which is a specific temperature.Specifically, when the room temperature is higher than the meltingpoint, the phase change material undergoes a phase change from solid toliquid, and, when the room temperature is lower than the melting point,the phase change material undergoes a phase change from liquid to solid.The melting point of the phase change material may be controlledaccording to the mode of the use thereof, and the phase change materialwhich exhibits solid/liquid phase transition at a temperature in therange of from about −20 to 120° C. can be appropriately used. Forexample, when the temperature in housing spaces of houses and the likeor interior spaces of automobiles, electric trains, aircraft,agricultural hothouses and the like is maintained at an appropriatetemperature in an attempt to save energy, appropriate temperaturemaintaining performance can be exhibited by mixing the phase changematerial having a melting point designed to a temperature suitable foreveryday life, specifically 10 to 35° C., preferably 15 to 30° C. Morespecifically, in the case of controlling the appropriate temperaturemaintaining performance in the season of winter or summer, for thepurpose of maintaining the heating effect in the winter, the phasechange material preferably having a melting point of about 18 to 28° C.,more preferably about 18 to 23° C. is mixed, and, for the purpose ofsuppressing the temperature rise in the summer, the phase changematerial preferably having a melting point of about 20 to 30° C., morepreferably about 25 to 30° C. is mixed. For achieving both effects, twoor more types of the phase change materials having different meltingpoints designed may be mixed. When an attempt is made to save energy forthe inside of a refrigerator of refrigeration equipment or the like, thephase change material having a melting point of about −10 to 5° C. maybe used.

The heat storage material used in one or more embodiments of the presentinvention preferably has a water content of 3% by mass or less, morepreferably 2.0% by mass or less, further preferably 1.5% by mass orless, especially preferably 1.2% by mass or less. When the water contentof the heat storage material during the preparation of the heat-storagecomposition is in the above range, formation of a very small blister ordepression in the obtained heat storage sheet can be easily suppressed,making it easy to obtain a heat storage sheet having advantageousappearance.

In one or more embodiments, the content of the heat storage material inthe heat storage sheet is preferably 10 to 80% by mass, more preferably20 to 70% by mass, further preferably 30 to 60% by mass. When thecontent of the heat storage material is in the above range, excellentheat storage effect and formability can be readily obtained. Further,when the content of the heat storage material is 10% by mass or more, itis easy to adjust the composition viscosity and the storage elasticmodulus to those in the respective ranges in one or more embodiments ofthe present invention.

[Heat-Storage Composition]

The heat-storage composition of one or more embodiments of the presentinvention is a heat-storage composition having a viscosity of 100 to1,000 dPa·s, as measured by a cylinder-type rotational viscometer(Viscotester). By virtue of having the above-mentioned viscosity, theheat-storage composition enables advantageous thick film formation, andexhibits excellent form retention properties in the thick filmapplication. The viscosity is preferably 120 dPa·s or more, morepreferably 150 dPa·s or more. The upper limit of the viscosity is morepreferably 800 dPa·s or less, further preferably 600 dPa·s or less,especially preferably 500 dPa·s or less.

In one or more embodiments, the viscosity can be measured under theconditions shown below.

Measuring apparatus: Viscotester VT-04 (manufactured by Rion Co., Ltd.)Conditions for measurement: temperature: 25° C., No. 2 rotor (62.5 rpm)

Further, in one or more embodiments of the present invention, the steadyshear viscosity at a shear rate of 10 [1/s] is preferably 50 Pa·s orless, more preferably 30 Pa·s or less. When the steady shear viscosityis in the above range, advantageous fluidity of the heat-storagecomposition during the application can be easily obtained, facilitatingimprovement of the application properties.

The steady shear viscosity is a steady shear viscosity at a shear ratein the range of from 0.1 to 700 [1/s] measured under conditions at atemperature of 25° C. in accordance with JIS K 7117-2. Specifically, thesteady shear viscosity is measured by means of rotational RheometerMCR102, manufactured by Anton Paar GmbH, using parallel plate PP50(diameter: 50 mm).

A sample to be used in the measurement is homogeneously dispersed usingHomogenizing Disper at about 500 rpm for 2 minutes to obtain ameasurement sample. It is also preferred that about 2 g of thecomposition to be measured is placed on a specimen carrier of arheometer and a parallel plate for measurement is brought downwards sothat the composition is sandwiched with a gap of about 1.1 to 1.3 mm,and pre-shear is preliminarily applied to the sandwiched sample in orderto make equal the states of the all samples before subjected to mainmeasurement, followed by the main measurement. Conditions for pre-shearare, for example, such that the shear rate is 10 [1/s] and theapplication time is 60 [sec].

The heat-storage composition of one or more embodiments of the presentinvention is a heat-storage composition having a storage elastic modulus(G′) of 3 Pa or more at 1 [rad/s], as measured by dynamicviscoelasticity measurement at a temperature of 25° C. and at a strainof 0.1%. The storage elastic modulus (G′) of the heat-storagecomposition is in the above range, and therefore the occurrence of slumpduring the thick film application can be advantageously suppressed,enabling formation of an excellent coating film having an increasedthickness. The storage elastic modulus (G′) is preferably 5 Pa or more,more preferably 8 Pa or more. The upper limit of the storage elasticmodulus (G′) is not particularly limited, but is preferably 200 Pa orless, more preferably 150 Pa or less.

Further, in one or more embodiments it is preferred that theheat-storage composition has a loss elastic modulus (G″) of 10 Pa ormore measured as mentioned above at 1 [rad/s]. The upper limit of theloss elastic modulus (G″) is preferably 200 Pa or less, more preferably150 Pa or less. When the loss elastic modulus (G″) of the heat-storagecomposition is in the above range, advantageous form retentionproperties and application properties can be readily obtained during thethick film application.

When the heat-storage composition of one or more embodiments of thepresent invention has a loss tangent (tan δ) of 3 or less at an angularfrequency of 1 [rad/s], as measured by dynamic viscoelasticitymeasurement, excellent form retention properties can be achieved duringthe thick film application, and the occurrence of slump can beadvantageously suppressed, and therefore a thick sheet can be easilyformed by application. The loss tangent is more preferably 2 or less,further preferably 1.5 or less. Further, the loss tangent is preferably0.3 or more, more preferably 0.5 or more.

The dynamic viscoelasticity is a dynamic viscoelasticity measured at anangular frequency of 0.3 to 100 rad/s under conditions at a temperatureof 25° C. and at a strain of 0.1% in accordance with JIS K 7244-10.Specifically, the dynamic viscoelasticity is measured by means ofrotational Rheometer MCR102, manufactured by Anton Paar GmbH, usingparallel plate PP50 (diameter: 50 mm).

In one or more embodiments, a sample to be used in the measurement ishomogeneously dispersed using Homogenizing Disper at about 500 rpm for 2minutes to obtain a measurement sample. It is also preferred that thecomponents for the composition to be measured are mixed and theresultant composition is allowed to stand for one hour, and then about 2g of the composition is placed on a specimen carrier of a rheometer anda parallel plate for measurement is brought downwards so that thecomposition is sandwiched with a gap of about 1.1 to 1.3 mm, andpre-shear is preliminarily applied to the sandwiched sample in order tomake equal the states of the all samples before subjected to mainmeasurement, followed by the main measurement. Conditions for pre-shearare, for example, such that the shear rate is 10 [1/s] and theapplication time is 60 [sec].

The heat-storage composition of one or more embodiments of the presentinvention is prepared by blending together the above-mentioned resincomponent and heat storage material. For example, when a vinyl chlorideresin is used as the thermoplastic resin, a method is preferred inwhich, using a vinyl sol coating liquid using vinyl chloride resinparticles as the heat-storage composition, a heat storage layer isformed by sol casting. By employing the above production method, formingcan be made without kneading using a mixer or the like, extrusion, orthe like, and thus the heat storage material is unlikely to sufferbreakage, so that the heat storage material is unlikely to ooze out ofthe obtained heat storage sheet. Further, by using the above method,forming at low temperatures is readily made, and therefore breakage ofthe heat storage material due to heat can be suppressed, and thus themethod can be especially preferably used.

When a vinyl sol coating liquid using a vinyl chloride resin is used asthe heat-storage composition of one or more embodiments, the amount ofthe vinyl chloride resin contained is preferably 10 to 80% by mass, morepreferably 20 to 70% by mass, further preferably 30 to 60% by mass,based on the mass of the solids contained in the heat-storagecomposition (components other than the solvent). The amount of theplasticizer contained, relative to 100 parts by mass of thethermoplastic resin contained in the composition, is preferably 30 to150 parts by mass, more preferably 30 to 120 parts by mass, furtherpreferably 40 to 100 parts by mass. Further, the amount of the containedheat storage material mixed into the composition is preferably 10 to 80%by mass, more preferably 20 to 70% by mass, further preferably 30 to 60%by mass, based on the mass of the solids contained in the composition.

In the heat-storage composition of one or more embodiments, anappropriate solvent can be used. As the solvent, the solvent used in thesol casting method for vinyl chloride resin can be appropriately used,and, especially, preferred examples of solvents include ketones, such asdiisobutyl ketone and methyl isobutyl ketone, esters, such as butylacetate, and glycol ethers. These solvents are preferred because theylikely slightly swell the resin at room temperature to help dispersionand likely promote melting or gelation of the resin in the heating step.These solvents may be used individually or in combination.

In one or more embodiments, a diluent solvent may be used together withthe above solvent. As the diluent solvent, a solvent which does notdissolve the resin and suppresses the swelling properties of thedispersing solvent can be preferably used. As such a diluent solvent,for example, a paraffin hydrocarbon, a naphthene hydrocarbon, anaromatic hydrocarbon, a terpene hydrocarbon, or the like can be used.

In the heat-storage composition of one or more embodiments, forsuppressing decomposition or deterioration, or discoloration causedmainly due to a dehydrochlorination reaction of the vinyl chlorideresin, a heat stabilizer is preferably used. As the heat stabilizer, forexample, a calcium/zinc stabilizer, an octyltin stabilizer, abarium/zinc stabilizer, or the like can be used. The amount of the heatstabilizer contained is preferably 0.5 to 10 parts by mass, relative to100 parts by mass of the vinyl chloride resin.

The heat-storage composition of one or more embodiments mayappropriately contain, if necessary, as a component other than thosementioned above, an additive, such as a viscosity depressant, adispersant, or an anti-foaming agent. The amount of each additivecontained is preferably 0.5 to 10 parts by mass, relative to 100 partsby mass of the vinyl chloride resin.

With respect to the heat storage sheet comprising a sol cast film of theheat-storage composition containing the vinyl chloride resin particlesand the heat storage material of one or more embodiments, a shear orpressure is not applied to the heat storage material during theproduction of the sheet, and therefore the heat storage material isunlikely to suffer breakage. Thus, despite the use of a resin material,the heat storage material is unlikely to ooze out of the sheet. Further,by virtue of having the heat storage material, the heat storage sheethas heat storage properties, and further can realize excellentflexibility. Furthermore, the heat storage sheet can be easily laminatedon another layer or processed, and therefore can be used in variousapplications or modes.

[Heat Storage Sheet]

The heat-storage composition of one or more embodiments of the presentinvention is applied or charged into a frame in an arbitrary form, andthen heated or dried, thus forming a heat storage sheet. An example of apreferred production method is a method in which the resin compositioncontaining a resin and a heat storage material is prepared, and thecomposition is applied onto a support to form a coating film, and thenthe coating film is heated at such a temperature that the coating filmtemperature becomes 150° C. or lower to form a heat storage sheet.

With respect to the support used in one or more embodiments, when theheat storage sheet is peeled off the support and circulated, used, orthe like, a support from which the obtained heat storage sheet can bepeeled, and which has a heat resistance at a temperature for the heatingstep can be appropriately used. When the heat storage sheet is used inthe form of being laminated on another functional layer or substrate,the functional layer or substrate may be used as a support.

When the heat storage sheet is peeled off a support, for example, aresin film used as a film for various steps can be preferably used as asupport. Examples of the resin films include polyester resin films, suchas a polyethylene terephthalate resin film and a polybutyleneterephthalate resin film. With respect to the thickness of the resinfilm, there is no particular limitation, but the resin film having athickness of about 25 to 100 μm is easy to handle and is readilyavailable.

With respect to the resin film used as a support, one having a surfacewhich has been subjected to release treatment can be preferably used.Examples of release treatment agents used in the release treatmentinclude an alkyd resin, an urethane resin, an olefin resin, and asilicone resin.

In a cast film forming method in which the heat-storage composition isapplied, a coating machine, such as a roll knife coater, a reverse-rollcoater, or a comma coater, can be used. Especially, there can bepreferably used a method in which the heat-storage resin composition isfed onto a support to form a coating film having a predeterminedthickness using a doctor knife or the like.

In one or more embodiments, the obtained coating film is gelled or curedby heating or drying to form a sheet. The heating temperature ispreferably such that the coating film temperature becomes 150° C. orlower, more preferably 140° C. or lower, further preferably 130° C. orlower, further preferably 120° C. or lower. By adjusting the coatingfilm temperature to the above-mentioned temperature, breakage of theheat storage material due to heat can be advantageously suppressed. Theheating time may be appropriately controlled according to the gelationrate or the like, but the heating time may be adjusted to about 10seconds to 10 minutes. The heating and drying, such as air-drying, maybe appropriately employed in combination.

When a solvent is used in the heat-storage composition of one or moreembodiments, removal of the solvent may be simultaneously performed inthe heating step, but it is also preferred that predrying is performedprior to the heating.

The above-formed heat storage sheet is subjected to a step in which theheat storage sheet is peeled off the support, and thus can be used as aheat storage sheet. The peeling may be appropriately conducted by anadvantageous method. The heat storage sheet can be circulated in thestate of being laminated on the support when the state of beinglaminated on the support is advantageous to various processing orlamination of the sheet.

In one or more embodiments, the thickness of the heat tstorage sheet maybe appropriately controlled according to the mode of the use thereof.For example, when applied to walls for a closed space and the like, fromthe viewpoint of readily obtaining advantageous heat storage effect, thethickness of the heat storage sheet is preferably 100 μm or more, morepreferably 500 μm or more, further 1 mm or more, especially preferably 3mm or more. With respect to the upper limit of the thickness, there isno particular limitation, but, when the organic heat storage layer ishandled in an independent form, for example, when the organic heatstorage layer in a sheet form is formed and then put on the inorganicsubstrate, from the viewpoint of readily obtaining advantageousflexibility and handling properties, the heat storage sheet is formedwith a thickness of preferably 20 mm or less, more preferably 10 mm orless, further preferably 6 mm or less. Even when the heat storage sheetin one or more embodiments of the present invention has a thickness of,for example, 500 μm or more, or a thickness as large as 1 mm or more, acrack or a defect is unlikely to be caused in the sheet being processedor carried, making it possible to realize excellent processability andhandling properties.

[Heat Storage Laminate]

It is preferred that the heat storage sheet in one or more embodimentsof the present invention is laminated on various types of functionallayers to form a heat storage laminate. For example, when the heatstorage sheet is laminated on an incombustible layer, such asincombustible paper or an incombustible substrate, it is possible toimprove the flame retardancy, and the resultant laminate is especiallypreferably applied to housing spaces. Further, for example, when theheat storage sheet is laminated on a thermal diffusion layer or a heatinsulating layer, the resultant laminate can more effectively exhibitheat storage properties. For applying the heat storage sheet to innerwalls and the like for housing spaces, a patterned layer or a decorativelayer can be formed on the heat storage sheet.

With respect to the incombustible layer of one or more embodiments,various types of incombustible substrates can be used, and, when theheat storage sheet is laminated on the incombustible substrate, it ispossible to impart quasi-incombustibility or incombustibility to thesheet. Examples of the incombustible substrates include inorganicsubstrates, such as plasterboard, a calcium silicate board, a flexibleboard, a cement board, and fiber-reinforced boards thereof.

Further, incombustible paper can be used as the incombustible layer ofone or more embodiments, and there can be mentioned a construction inwhich incombustible paper is laminated on one surface or both surfacesof the heat storage sheet in one or more embodiments of the presentinvention. The construction in which incombustible paper is laminated onone surface of the heat storage sheet may be a construction in which theheat storage sheet in one or more embodiments of the present inventionis put on incombustible paper, but a construction in which thecomposition forming the heat storage sheet in one or more embodiments ofthe present invention is directly applied onto incombustible paper andsubjected to gelation is preferred because the formation of the laminateis easy. The construction in which the heat storage sheet hasincombustible paper on both surfaces thereof may be a construction inwhich incombustible paper is put on both surfaces of the heat storagesheet in one or more embodiments of the present invention, but thelaminate can be easily formed by applying the heat-storage compositiononto incombustible paper and subjecting the applied composition togelation, and putting the heat storage sheet surfaces of the resultantincombustible paper laminated heat storage sheets on each other.Further, a construction can be preferably used in which theabove-mentioned incombustible substrate is further laminated on theabove construction having incombustible paper laminated on one surfaceor both surfaces of the heat storage sheet.

With respect to the incombustible paper of one or more embodiments,there is no particular limitation as long as it has incombustibility,but, for example, paper having applied thereto, impregnated with, orcontaining therein a flame retardant can be used. Examples of flameretardants include metal hydroxides, such as magnesium hydroxide andaluminum hydroxide, basic compounds, such as phosphates, borates, andsulfamates, and glass fibers.

In one or more embodiments where the heat storage laminate having aconstruction in which a thermal diffusion layer is laminated on the heatstorage layer is applied to a closed space, such as an interior space,the thermal diffusion layer exhibits an effect that causes the heatinside the interior space to be uniform, and further can disperse theheat from the interior space (e.g., closed spaces, such as housingspaces of houses and the like, interior spaces of automobiles, electrictrains, aircraft and the like, the inside of a refrigerator ofrefrigerator trucks, and the inside of aircraft) to conduct the heat tothe heat storage layer with a less thermal resistance. In the heatstorage layer, the heat storage particles cause absorption of heatinside the interior space and emission of heat to the interior space,making it possible to control the temperature environment of theinterior space to be at an appropriate temperature.

As the thermal diffusion layer of one or more embodiments, a layerhaving a thermal conductivity as high as 5 to 400 W/m·K can bepreferably used. By virtue of high thermal conductivity, the locallyconcentrated heat is diffused to be conducted to the heat storage layer,making it possible to improve the thermal efficiency and cause the roomtemperature to be uniform.

Examples of materials for the thermal diffusion layer include aluminum,copper, iron, and graphite. In one or more embodiments of the presentinvention, particularly, aluminum can be preferably used. The reason whyaluminum is preferred is, for example, that aluminum also exhibits aheat insulating effect due to reflection of radiant heat. Particularly,in a heating apparatus using radiant heat, the heat insulating effectcan improve the heating efficiency. As examples of heating apparatusesmainly using radiant heat, there can be mentioned electric floorheating, hot-water type floor heating, and an infrared heater. Also fromthe viewpoint of preventing disasters, it is possible to improve theflame retardancy performance.

With respect to the form of the thermal diffusion layer of one or moreembodiments, an appropriate form of a layer made of a sheet of theabove-mentioned material, a deposited layer of the above material, orthe like can be used. When aluminum is used as a material for thethermal diffusion layer, for example, a thermal diffusion layer havingstretchability, such as an aluminum foil or an aluminum deposited layer,can be preferably used.

With respect to the thickness of the thermal diffusion layer of one ormore embodiments, there is no particular limitation, but the thermaldiffusion layer preferably has a thickness of about 3 to 500 μm becauseit is easy to secure advantageous thermal diffusion properties andhandling properties.

In one or more embodiments where the heat storage laminate has aconstruction in which a heat insulating layer is laminated on the heatstorage layer, the heat storage layer effectively performs absorption ofheat and emission of heat on the interior space side, so that theappropriate temperature maintaining effect for the interior space can beespecially advantageously exhibited. Further, this construction is alsoeffective in preventing the heat in the interior space from flowing out,or reducing the effect of the heat from the outside air. Utilizing acombination of these effects, the heat storage laminate in one or moreembodiments of the present invention can suppress a change of thetemperature in the interior space to retain the interior space at anappropriate temperature. Further, when an air-conditioning apparatus,such as an air-conditioner or refrigeration equipment, is used, it ispossible to reduce the energy consumption of the apparatus. Thus, theheat storage laminate can advantageously contribute to energy savingsfor interior spaces.

As the heat insulating layer of one or more embodiments, a layer havinga thermal conductivity of less than 0.1 W/m·K can be preferably used.The heat insulating layer exhibits an effect such that the heat isprevented from flowing out of the heat storage layer to the outside airand further the effect of the outside air on the temperature is reduced.With respect to the heat insulating layer, there is no particularlimitation as long as it can form a layer having a thermal conductivityof less than 0.1 W/m·K, and, for example, a heat insulating sheet, suchas a foamed resin sheet, or a resin sheet containing a heat insulatingmaterial, or a heat insulating board, such as extrusion methodpolystyrene, bead method polystyrene, a polyethylene foam, an urethanefoam, or a phenol foam, can be appropriately used. Especially, a heatinsulating sheet is preferred because it is easy to secure workingproperties, and a resin sheet containing a heat insulating material ismore preferred because the thermal conductivity can be reduced. Further,a foamed sheet is preferred because it is readily available andinexpensive.

When the heat insulating layer is in a sheet form, it is easy to secureworking properties, and, especially, it is preferred that a measuredvalue of the heat insulating layer using a cylindrical mandrel flextesting machine (JIS K 5600) is 2 to 32 mm, in terms of a mandreldiameter.

The heat insulating material used in the heat insulating layer improvesthe heat insulating properties of the heat storage laminate, andexamples of heat insulating materials include porous silica, porousacryl, hollow glass beads, vacuum beads, and hollow fibers. As the heatinsulating material 5, a known heat insulating material may be used. Inone or more embodiments of the present invention, particularly, porousacryl can be preferably used. The particle diameter of the heatinsulating material is not limited, but is preferably about 1 to 300 μm.

When a resin sheet containing a heat insulating material is used as theheat insulating layer, the heat insulating material is mixed into aresin material as a base and subjected to sheet forming. Examples ofresin materials include, as mentioned above, polyvinyl chloride,polyphenylene sulfide, polypropylene, polyethylene, polyester, and anacrylonitrile-butadiene-styrene resin. As polyester, A-PET, PET-G, orthe like can be used. Of these, from the viewpoint of low combustibilityupon a fire, a vinyl chloride resin having self-extinguishing propertiescan be preferably used.

As a sheet forming method of one or more embodiments, for example, avinyl chloride resin, a plasticizer, and a heat insulating material aresubjected to sheet forming using a forming machine for extrusion,calendering, or the like.

In one or more embodiments, the content of the heat insulating materialin the heat insulating layer is preferably 20% by mass or more, morepreferably 20 to 80% by mass, further preferably 30 to 80% by mass,especially preferably 40 to 80% by mass, based on the mass of the heatinsulating layer. When the content of the heat insulating material is inthe above range, the heat insulating effect can be advantageouslyexhibited, and the formation of the heat insulating layer isfacilitated.

In the heat insulating layer of one or more embodiments, if necessary,an additive, such as a plasticizer or a flame retardant, may beincorporated.

With respect to the thickness of the heat insulating layer of one ormore embodiments, there is no particular limitation, but the larger thethickness, the more excellent the heat retaining properties for interiorspaces the heat insulating layer exhibits. For securing thestretchability or working properties of the sheet, the thickness of theheat insulating layer is preferably about 50 to 3,000 μm.

The heat storage sheet formed from the heat-storage composition of oneor more embodiments of the present invention is advantageously usedmainly in the interior material application for inner walls, ceilings,floors, and the like of buildings, but can be applied to coatingmaterials for sash window frame and interior trims for vehicles and thelike. Further, the heat storage sheet can be used not only in walls,floors, and ceilings of buildings but also in interior spaces ofautomobiles, electric trains, aircraft and the like. Furthermore, theheat storage sheet can be used as a low-temperature retaining materialfor refrigeration equipment, or a low-temperature maintaining materialfor electric parts which generate heat, e.g., a CPU and a storagebattery for personal computer. The heat storage sheet and a heater, suchas a heating element in a plane form, may be used in combination toexhibit an energy saving effect due to heat storage.

EXAMPLES Example 1

100 Parts by mass of polyvinyl chloride resin particles having apolymerization degree of 900 (ZEST PQ92, manufactured by Shin Dai-ichiVinyl Corporation), 62 parts by mass of an epoxy plasticizer (MonocizerW-150, manufactured by DIC Corporation; viscosity: 85 mPa·s; gelationend-point temperature: 121° C.), 3 parts by mass of a heat stabilizer(GLECK ML-610A, manufactured by Showa Varnish Co., Ltd.), and, as otheradditives, 6 parts by mass of a viscosity depressant (viscositydepressant VISCOBYK-5125, manufactured by BYK Japan KK) and 6 parts bymass of a dispersant (Disperplast-1150, manufactured by BYK Japan KK),and 90 parts by mass of a phase change material (Thermo Memory FP-27,manufactured by Mitsubishi Paper Mills Limited; average particlediameter: 50 μm; melting point: 27° C.; water content: 0.9% by mass) inthe form of microcapsules having a paraffin encapsulated using an outershell made of a melamine resin were blended together to prepare aheat-storage composition. A calculated value of the HSP distance betweenthe plasticizer and the phase change material used was 22.30, acalculated value of the HSP distance between the plasticizer and thevinyl chloride resin was 4.6, and an absorption of the plasticizer into100 parts by mass of the phase change material used was 81 parts bymass.

Example 2

A heat-storage composition was prepared in substantially the same manneras in Example 1 except that the amount of the incorporated phase changematerial used in Example 1 was changed to 110 parts by mass.

Example 3

A heat-storage composition was prepared in substantially the same manneras in Example 1 except that, instead of the epoxy plasticizer used inExample 1, a polyester plasticizer (Polycizer W-230H, manufactured byDIC Corporation; viscosity: 220 mPa·s; gelation end-point temperature:136° C.) was used. A calculated value of the HSP distance between theplasticizer and the phase change material used was 23.20, a calculatedvalue of the HSP distance between the plasticizer and the vinyl chlorideresin was 6.4, and an absorption of the plasticizer into 100 parts bymass of the phase change material used was 72 parts by mass.

Example 4

A heat-storage composition was prepared in substantially the same manneras in Example 3 except that the amount of the incorporated phase changematerial used in Example 3 was changed to 60 parts by mass.

Example 5

A heat-storage composition was prepared in substantially the same manneras in Example 1 except that the amount of the incorporated polyvinylchloride resin particles used in Example 1 was changed to 60 parts bymass.

Example 6

A heat-storage composition was prepared in substantially the same manneras in Example 1 except that, instead of the polyvinyl chloride resinparticles having a polymerization degree of 900 used in Example 1,polyvinyl chloride resin particles having a polymerization degree of1,800 (ZEST PQHT, manufactured by Shin Dai-ichi Vinyl Corporation) wereused, and that the amount of the incorporated phase change material usedin Example 1 was changed to 80 parts by mass.

Example 7

A heat-storage composition was prepared in substantially the same manneras in Example 1 except that, instead of the 90 parts by mass of thephase change material used in Example 1, 82 parts by mass of a phasechange material (Micronal DS5001X, manufactured by BASF AG; particlediameter: 100 to 300 μm; melting point: 26° C.; water content: 0.8% bymass) in the form of microcapsules having a paraffin encapsulated usingan outer shell made of a polymethyl methacrylate (PMMA) resin was used.A calculated value of the HSP distance between the plasticizer and thephase change material used was 8.88, a calculated value of the HSPdistance between the plasticizer and the vinyl chloride resin was 4.6,and an absorption of the plasticizer into 100 parts by mass of the phasechange material was 129 parts by mass.

Example 8

100 Parts by mass of polyvinyl chloride resin particles having apolymerization degree of 900 (ZEST PQ92, manufactured by Shin Dai-ichiVinyl Corporation), 105 parts by mass of an epoxy plasticizer (MonocizerW-150, manufactured by DIC Corporation; viscosity: 85 mPa·s; gelationend-point temperature: 121° C.), 3 parts by mass of a heat stabilizer(GLECK ML-610A, manufactured by Showa Varnish Co., Ltd.), and, as otheradditives, 12 parts by mass of a viscosity depressant (viscositydepressant VISCOBYK-5125, manufactured by BYK Japan KK) and 12 parts bymass of a dispersant (Disperplast-1150, manufactured by BYK Japan KK),and 160 parts by mass of a phase change material (Thermo Memory FP-27,manufactured by Mitsubishi Paper Mills Limited; average particlediameter: 50 μm; melting point: 27° C.; water content: 0.9% by mass) inthe form of microcapsules having a paraffin encapsulated using an outershell made of a melamine resin were blended together to prepare aheat-storage composition.

Example 9

100 Parts by mass of polyvinyl chloride resin particles having apolymerization degree of 900 (ZEST PQ92, manufactured by Shin Dai-ichiVinyl Corporation), 50 parts by mass of an epoxy plasticizer (MonocizerW-150, manufactured by DIC Corporation; viscosity: 85 mPa·s; gelationend-point temperature: 121° C.), 3 parts by mass of a heat stabilizer(GLECK ML-610A, manufactured by Showa Varnish Co., Ltd.), and 25 partsby mass of a phase change material (Thermo Memory FP-27, manufactured byMitsubishi Paper Mills Limited; average particle diameter: 50 μm;melting point: 27° C.; water content: 0.9% by mass) in the form ofmicrocapsules having a paraffin encapsulated using an outer shell madeof a melamine resin were blended together to prepare a heat-storagecomposition.

Example 10

A heat-storage composition was prepared in substantially the same manneras in Example 7 except that the amount of the incorporated phase changematerial used in Example 7 was changed to 68 parts by mass.

Example 11

A heat-storage composition was prepared in substantially the same manneras in Example 1 except that the amount of the incorporated polyvinylchloride resin particles used in Example 1 was changed to 60 parts bymass, and that the amount of the incorporated phase change material waschanged to 100 parts by mass.

Example 12

A heat-storage composition was prepared in substantially the same manneras in Example 11 except that the amount of the incorporated phase changematerial used in Example 11 was changed to 130 parts by mass.

Example 13

A heat-storage composition was prepared in substantially the same manneras in Example 1 except that, instead of the epoxy plasticizer used inExample 1, a benzoic acid plasticizer (Monocizer PB-10, manufactured byDIC Corporation; viscosity: 80 mPa·s; gelation end-point temperature:100° C. or lower) was used. A calculated value of the HSP distancebetween the plasticizer and the phase change material used was 17.10, acalculated value of the HSP distance between the plasticizer and thevinyl chloride resin was 1.4, and an absorption of the plasticizer into100 parts by mass of the phase change material used was 96 parts bymass.

Comparative Example 1

A heat-storage composition was prepared in substantially the same manneras in Example 1 except that the amount of the incorporated phase changematerial used in Example 1 was changed to 150 parts by mass.

Comparative Example 2

A heat-storage composition was prepared in substantially the same manneras in Example 1 except that the amount of the incorporated phase changematerial used in Example 1 was changed to 50 parts by mass.

Comparative Example 3

A heat-storage composition was prepared in substantially the same manneras in Example 1 except that, instead of the epoxy plasticizer used inExample 1, a benzoic acid plasticizer (W-83, manufactured by DICCorporation; viscosity: 220 mPa·s; gelation end-point temperature: 136°C.) was used, and that the amount of the incorporated phase changematerial used in Example 1 was changed to 30 parts by mass. A calculatedvalue of the HSP distance between the plasticizer and the phase changematerial used was 18.90, a calculated value of the HSP distance betweenthe plasticizer and the vinyl chloride resin was 1.7, and an absorptionof the plasticizer into 100 parts by mass of the phase change materialused was 90 parts by mass.

The methods for evaluating the heat-storage compositions obtained in theExamples and the Comparative Examples above and the like are as shownbelow.

<Conditions for Measurement of Plasticizer Viscosity>

Measuring apparatus: Brookfield viscometer (“DVM-B type”, manufacturedby Tokyo Keiki Co., Ltd.)Conditions for measurement: temperature: 25° C., No. 2 rotor, 30 rpm

<Plasticizer Absorption>

An absorption of a plasticizer into a heat storage material was measuredby the below-described method in accordance with JIS K5101-13-1. Asample obtained by weighing 1 g (2 g in Example 5) of a heat storagematerial was placed on a glass plate, and a plasticizer was dropwiseadded to the sample from a burette so that 4 to 5 droplets of theplasticizer were added at a time, and the plasticizer was kneaded intothe sample using a palette knife made of steel. This was repeated andthe dropwise addition of the plasticizer was continued until a solidmass of the plasticizer and the sample was formed. Thereafter, onedroplet of the plasticizer was added at a time and completely kneadedinto the mass, and this was repeated, and a point in time when the masshad become a smooth paste was determined as an end point, and theabsorption at the end point was taken as an absorption of theplasticizer.

<Conditions for Measurement of Heat-Storage Composition Viscosity>(Cylinder-Type Rotational Viscometer)

With respect to the heat-storage compositions obtained in the Examplesand the Comparative Examples, the materials constituting eachcomposition were mixed together so that the total weight became 300 g,and homogeneously dispersed using Homogenizing Disper at about 500 rpmfor 2 minutes to obtain a measurement sample. The liquid temperature ofthe measurement sample was adjusted to 25° C., and a viscosity of thesample was measured by means of a cylinder-type rotational viscometer.

Measuring apparatus: Viscotester VT-04 (manufactured by Rion Co., Ltd.)Conditions for measurement: temperature: 25° C., No. 2 rotor (62.5 rpm)

<Steady Shear Viscosity>

With respect to the heat-storage compositions obtained in the Examplesand the Comparative Examples, a steady shear viscosity was measured inaccordance with JIS K 7117-2 at a shear rate in the range of from 0.1 to700 [1/s] under conditions at a temperature of 25° C. by means ofrotational Rheometer MCR102, manufactured by Anton Paar GmbH, usingparallel plate PP50 (diameter: 50 mm). The measurement was conducted asfollows. The composition was blended and then homogeneously dispersedusing Homogenizing Disper at about 500 rpm for 2 minutes to obtain ameasurement sample, and about 2 g of the sample was placed on a specimencarrier of the rheometer and a parallel plate for measurement wasbrought downwards so that the sample was sandwiched with a gap of about1.1 to 1.3 mm, and pre-shear was preliminarily applied to the sandwichedsample in order to make equal the states of the all samples beforesubjected to main measurement, followed by the main measurement.Conditions for pre-shear were such that the shear rate was 10 [1/s] andthe application time was 60 [sec].

<Dynamic Viscoelasticity Measurement>

With respect to the heat-storage compositions obtained in the Examplesand the Comparative Examples, a dynamic viscoelasticity was measured inaccordance with JIS K 7244-10 at an angular frequency of 0.3 to 100rad/s under conditions at a temperature of 25° C. and at a strain of0.1% by means of rotational Rheometer MCR102, manufactured by Anton PaarGmbH, using parallel plate PP50 (diameter: 50 mm). The measurement wasconducted as follows. The composition was blended and then homogeneouslydispersed using Homogenizing Disper at about 500 rpm for 2 minutes toobtain a measurement sample, and about 2 g the sample was placed on aspecimen carrier of the rheometer and a parallel plate for measurementwas brought downwards so that the sample was sandwiched with a gap ofabout 1.1 to 1.3 mm, and pre-shear was preliminarily applied to thesandwiched sample in order to make equal the states of the all samplesbefore subjected to main measurement, followed by the main measurement.Conditions for pre-shear were such that the shear rate was 10 [1/s] andthe application time was 60 [sec].

<Application Properties>

With respect to the heat-storage compositions obtained in the Examplesand the Comparative Examples, a coating film having a thickness of 3 mmwas formed using an automatic applicator.

The obtained coating film was visually evaluated in accordance with thecriteria shown below.

◯: In the entire application area, continuous coating film formation waspossible.

X: In the application area, a coating defect was caused in the appliedcomposition, and continuous coating film formation was impossible.

<Evaluation of Thick-Film Form Retention Properties>

With respect to the heat-storage compositions obtained in the Examplesand the Comparative Examples, 6 g of the composition was flowed onto asteel plate at a point for 15 seconds, and allowed to stand for 60seconds, and then subjected to gelation by heating at a dryertemperature of 150° C. for 8 minutes to obtain a heat storage sheet. Anarea and a thickness of the obtained heat storage sheet were measured,and evaluated in accordance with the criteria shown below.

◯: The thickness is 2 mm or more and the area is 50 cm2 or less.

X: The thickness is less than 2 mm and the area is more than 50 cm2.

<Measurement of a Water Content>

With respect to the heat-storage compositions obtained in the Examplesand the Comparative Examples, a water content was measured in accordancewith JIS K0068 Water content measurement method for chemical products b)drying loss method.

10 g of each of the heat-storage compositions obtained in the Examplesand the Comparative Examples was placed in a flat weighing bottle(specified in JIS R 3503; body diameter: 60 mm×height: 30=; capacity: 25ml), and the weighing bottle was placed in a dryer at 105° C. and a massof the bottle was measured every one hour until the mass became aconstant mass (constant mass: a mass at the time when a differencebetween a mass and the mass previously measured is 1/1,000 or less).

W=(S1−S2)/(S1−S3)×100

W: Water content (%)

S1: Mass (g) of the sample and the weighing bottle before dried

S2: Mass (g) of the sample and the weighing bottle after dried

S3: Mass (g) of the weighing bottle

<Evaluation of Appearance>

The heat-storage compositions obtained in the Examples and theComparative Examples were individually applied onto a steel plate sothat the thickness of the applied composition was 3 mm, and subjected togelation by heating at a dryer temperature of 150° C. for 8 minutes toobtain a heat storage sheet. With respect to the obtained heat storagesheet, a portion 10 cm square was checked whether or not there was ablister, and evaluated in accordance with the criteria shown below.

⊙: A blister or depression having a diameter of 5 mm or more is notfound.

◯: The number of blisters or depressions having a diameter of 5 mm ormore is less than 5.

X: The number of blisters or depressions having a diameter of 5 mm ormore is 5 or more.

TABLE 1 Example Example Example Example Example Example Example ExampleExample 1 2 3 4 5 6 7 8 9 Viscotester 150 280 270 160 130 150 220 160150 viscosity [dPa · s] Steady shear 17.6 27.2 23.6 10.2 9.4 10.3 31.115.4 12.9 viscosity [dPa · s] Storage elastic 10.5 17.6 8.3 3.5 7.1 6.448.4 13.4 17.3 modulus (ω = 1) [Pa] Loss elastic modulus 15.7 24.2 16.29.4 10.8 10.7 55.3 16.9 14.8 (ω = 1) [Pa] Application ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘properties Thick-film form ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ retention propertiesEvaluation of ⊙ ⊙ ⊙ ⊙ ⊙ ⊙ ⊙ ⊙ ⊙ appearance

TABLE 2 Comparative Comparative Comparative Example Example ExampleExample Example Example Example 10 11 12 13 1 2 3 Viscotester viscosity170 170 300 300 1100 <100 200 [dPa · s] Steady shear viscosity 29.4 43.5135 23.6 — 4.6 11.7 [dPa · s] Storage elastic modulus 14.5 34.4 117 14.6— 1.8 1.6 (ω = 1) [Pa] Loss elastic modulus 25.5 26.5 66.7 18.6 — 4.98.2 (ω = 1) [Pa] Application properties ∘ ∘ ∘ ∘ x ∘ ∘ Thick-film form ∘∘ ∘ ∘ — x x retention properties Evaluation of ⊙ ⊙ ⊙ ⊙ — ⊙ ⊙ appearance

As apparent from the above tables, with respect to all the heat-storagecompositions in Examples 1 to 13, the heat storage sheet being formedfrom each composition retained a maximum thickness of 2 mm or more andhad a sheet area of 50 cm2 or less, and thus had advantageous thick filmapplication properties despite containing the heat storage particles,and had advantageous thick-film form retention properties such thatslump or the like did not occur. Particularly, the compositions inExamples 1 to 11 and 13 had a sheet area in the range of from 30 to 50cm2, and were especially excellent in the application properties and thethick-film form retention properties. Further, the composition inExample 12 was excellent in the thick film formation. On the other hand,the compositions in Comparative Examples 1 to 3 did not haveadvantageous application properties or thick film applicationproperties.

Example 14

A heat-storage composition was prepared in substantially the same manneras in Example 1 except that a phase change material having a watercontent of 1.5% by mass was used. Using the obtained heat-storagecomposition, a heat storage sheet was formed by the same method as themethod for <Evaluation of appearance>, and evaluation of the appearanceof the sheet was made. The result of the evaluation was ⊙ (a blister ordepression having a diameter of 5 mm or more is not found).

Example 15

A heat storage sheet was formed in substantially the same manner as inExample 14 except that a phase change material having a water content of2.1% by mass was used, and evaluation of the appearance of the sheet wasmade. The result of the evaluation was ◯ (the number of blisters ordepressions having a diameter of 5 mm or more is less than 5).

Example 16

A heat storage sheet was formed in substantially the same manner as inExample 15 except that the drying temperature was changed to 130° C.,and evaluation of the appearance of the sheet was made. The result ofthe evaluation was ⊙ (a blister or depression having a diameter of 5 mmor more is not found).

Example 17

A heat storage sheet was formed in substantially the same manner as inExample 14 except that the same heat-storage composition as in Example 1was used as a heat-storage composition, and that the drying temperaturewas changed to 165° C., and evaluation of the appearance of the sheetwas made. The result of the evaluation was ⊙ (the number of blisters ordepressions having a diameter of 5 mm or more is less than 5).

Although the disclosure has been described with respect to only alimited number of embodiments, those skilled in the art, having benefitof this disclosure, will appreciate that various other embodiments maybe devised without departing from the scope of the present invention.Accordingly, the scope of the invention should be limited only by theattached claims.

What is claimed is:
 1. A heat-storage composition, comprising: a resin; and a heat storage material, wherein the composition has a viscosity of 100 to 1,000 dPa·s, as measured with a cylinder-type rotational viscometer, and a storage elastic modulus (G′) of 3 Pa or more at an angular frequency of 1 rad/s, as measured by a dynamic viscoelasticity measurement method at a temperature of 25° C. and at a strain of 0.1%.
 2. The composition according to claim 1, wherein the composition has a loss elastic modulus (G″) of 10 Pa or more at an angular frequency of 1 rad/s, as measured by a dynamic viscoelasticity measurement method at a temperature of 25° C. and at a strain of 0.1%.
 3. The composition according to claim 1, wherein the composition has a steady shear viscosity of 30 Pa·s or less.
 4. The composition according to claim 1, wherein the composition comprises 10 to 80% by mass of the heat storage material.
 5. The composition according to claim 1, wherein the resin is a thermoplastic resin.
 6. The composition according to claim 1, further comprising a plasticizer.
 7. The composition according to claim 6, wherein 100 parts by mass of the heat storage material absorbs 30 to 150 parts by mass of the plasticizer.
 8. The composition according to claim 6, wherein the plasticizer is an epoxy plasticizer.
 9. The composition according to claim 1, wherein the heat storage material is a plurality of microcapsules, wherein each of the microcapsules comprises a resin outer shell and a phase change material that is contained within the resin outer shell.
 10. The composition according to claim 1, wherein the heat storage material has a water content of 3% by mass or less.
 11. A method for producing a heat storage sheet, the method comprising: casting a heat-storage composition to forma coating film; and drying the coating film by heating at a temperature of 150° C. or lower, wherein the heat-storage composition comprises: a resin; and a heat storage material, wherein the heat-storage composition has a viscosity of 100 to 1,000 dPa·s, as measured with a cylinder-type rotational viscometer, and a storage elastic modulus (G′) of 3 Pa or more at an angular frequency of 1 rad/s, as measured by a dynamic viscoelasticity measurement method at a temperature of 25° C. and at a strain of 0.1%.
 12. The method according to claim 11, wherein the heat storage sheet obtained after drying has a thickness of 1 mm or more.
 13. The method according to claim 11, wherein the heat storage material has a water content of 3% by mass or less. 